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Anti-Labour sentiment in Scotland has been rising since last year's referendum

"Bow to your masters."

The sign was one of many held up by the dozens of protesters on hand to greet Labour supporters as they arrived in Glasgow for a Friday night speech by party leader Ed Miliband.

It was tangible proof that Scotland, once an impregnable Labour redoubt, has become increasingly hostile territory for the party - and the political implications for governing the UK are significant.

Mr Miliband, along with leaders of the Scottish Labour Party, appeared in a windowless room inside a massive aquatic complex, safe from the chaotic scene outside. Although he spoke to a friendly audience, his message was tailored to left-leaning voters throughout the region, which recent polls indicate may abandon Labour for the Scottish National Party in droves on election day Thursday.

"Nationalism never built a single school or lifted people out of poverty," Mr Miliband said, referring to Scotland's long history of Labour support. He painted a dire picture of David Cameron's Conservative Party holding on to power if Labour loses control of 50-plus seats in Scotland. He asserted that he would never join in a governing coalition with the SNP, "which wants to break up the United Kingdom".

"Think of your grandparents, moms and dads," he said, "who delivered leaflets and knocked on doors. What would they want us to do today? They wouldn't want Scotland to be David Cameron's last, best hope."

One member of the crowd was Maureen Burke, a long-time Labour supporter who has been attempting to convince her friends and neighbours not to abandon their party.

"I'm going door to door and speaking with people, and the Labour voters are there," she said. "We just have to be sure that they know that our vision is still the same as it's always been and we're working for them."

While Mr Miliband and his Labour supporters appeal to the long ties between Scotland and the Labour Party, the roots of Scottish nationalism go back much farther. From small outposts in the rugged Highlands like Glenfinnan and Glencoe to the cities of Edinburgh and Glasgow, artefacts and evidence of Scotland's storied history as an independent kingdom are everywhere. And the region is dotted with monuments to uprisings against the English rulers to the south, all of which eventually ended in defeat, slaughter or both.

The Scottish people have always taken pride in their heritage and unique culture - but it's only recently, in the run up to the 2014 referendum on Scottish independence, that this pride has translated into a formidable political identity.

Although Scottish voters elected to remain in the UK by a margin of 10%, the energy from the vote has translated into backing for SNP parliamentary candidates this general election. What's more, the memory of Labour leaders standing alongside Tory officials urging a no vote burns in the minds of many of the SNP supporters to this day.

"I was absolutely gutted," says Fay Kennedy of the perceived alliance. "That's when they were really dead to us."

A former Labour backer turned SNP volunteer in Kirkcaldy, a town on the coast north of Edinburgh, Kennedy says Labour and the Conservatives are now "cut from the same cloth".

While the 45% of the population who voted yes wasn't enough to carry the day last September, as campaign guru Nate Silver points out it is more than enough to triumph in a "first past the post" parliamentary race where a plurality of the vote is enough to achieve victory.

On Sunday night in Edinburgh the leaders of the four major Scottish parties - Conservative, SNP, Labour and the Liberal Democrats - gathered a final time to debate. Once again Labour's Jim Murphy and SNP leader Nicola Sturgeon clashed over whether the two parties would be able to work together to form a left-wing government if they have enough seats after Thursday's election - and what the SNP's true motivations are.

"This election is not about independence," Ms Sturgeon said. "It's about making Scotland's voice heard."

Mr Murphy countered: "A vote for the SNP will let the Tories back in", adding that Ms Sturgeon refuses to rule out voting against a Labour budget if it doesn't advance their policies, such as rescinding all austerity cuts to social programmes.

Meanwhile the Conservative Party's Ruth Davidson echoed Mr Cameron's repeated warnings that a vote for Labour is a vote for a party that would be beholden to Scotland's agenda.

As the audience members streamed out of the debate site, most minds appeared to have been made up already.

"The SNP is only interested in one thing, which is independence," says Andrew Wilson, a Labour supporter. "That's all they exist for. They're not interested in the welfare of the UK as a whole."

Sophie Lejea, an SNP backer, says that her party will give the Scottish people a "louder voice in Westminster".

"Labour to me are red Tories, that's all they are," she adds. "They used to be for the working person, to speak up for them, but now they're not the same anymore."

"Red Tories" - it's a term that's cropping again and again in Scotland, mentioned by nationalists and featured on the ubiquitous "Red Tories Out" stickers that seem to be plastered everywhere.

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The Scottish National Party has become a dominant force in pushing Labour to the sidelines in Scotland

It's a reference to the Labour Party's symbol, the red rose, and sometimes gives the nationalist movement the feeling of a subversive guerrilla resistance effort.

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A new catchphrase in Scotland says that Tories and Labour are 'cut from the same cloth'

The Scottish independence movement may have been halted, at least temporarily, last year. But the nationalist drive appears to be stronger than ever.